OK ... you don't say the price, but if it was US$18.88, then all is fine.
There are a number of technical problems on the Limewire site at present... including the fact that upgrading pro versions seems to be almost impossible unless you go direct to your personal download page.
I personally do not recommend updating from 4.9.37. I have just done it myself and have had some problems that hopefully will be removed in a later version than4.10.0
The upgrades are not automatic. You need to install the upgrade your self
I advise you to wait until the middle of January and keep an eye on the forums for news and views of later releases.
I advise you to make an archive copy of 4.9.37 pro, if you do chose to update, so that you can return to it if you wish otherwise it will be deleted by installing aa newer version.
If it's not too much of a pain ignore the update recomendation notice
I hope this helps